Valve apparatus for regulating a heat exchange liquid

1. A valve apparatus for regulating flow of a heat exchange liquid, the valve apparatus being adapted for connection to a heat exchanger having flow passages for heat exchange between said heat exchange liquid and a primary liquid having a temperature, operation of the valve apparatus being dependent on the temperature of said primary liquid, said valve apparatus comprising: a valve housing having first and second chambers formed therein, first inlet and outlet ports for flow of said primary liquid into and out of said first chamber, further ports for flow of said heat exchange liquid at either an elevated temperature or at a lower temperature into and out of said second chamber; a linear actuator mounted in said valve housing, said actuator including an actuator body containing wax and a piston made of a heat insulating plastic material and movable to an extended position by expansion of said wax due to a predetermined increase in the temperature of said wax, at least a substantial portion of said actuator body being located in said first chamber so that, during use of said apparatus, the temperature of the actuator body and said wax is substantially determined by the existing temperature of said primary liquid flowing through said first chamber, said actuator body having an end portion adjacent said second chamber made of a heat insulating plastic material; and a valve mechanism operable by said linear actuator and operably engaged by said piston for movement therewith, said valve mechanism being located in said second chamber and capable of controlling the flow of both said heat exchange liquid at said elevated temperature and said heat exchange liquid at said lower temperature through said second chamber, said valve mechanism including a spool having a first end engaged by said piston, a first valve closure arranged on said spool, and a second end section located opposite said first end and slidably supported in said valve housing; and a primary spring mounted in said second chamber so as to bias said spool to a valve closing position where said valve closure engages a first valve seat formed in said valve housing, wherein during use of said valve apparatus, operation of the linear actuator is substantially unaffected by the temperature of said heat exchange liquid flowing through the second chamber.

2. A valve apparatus according to claim 1 wherein said valve mechanism further includes a second valve closure slidably mounted on said spool in said second chamber and movable between an open position, which allows said heat exchange liquid at said elevated temperature to flow through said second chamber during use of the valve apparatus, and a closed position where said second valve closure engages a second valve seat formed in said valve housing and prevents said heat exchange liquid at said elevated temperature from flowing through said second chamber.

3. A valve apparatus according to claim 2 wherein said valve mechanism further includes a secondary spring arranged on said spool and positioned in said second chamber and said secondary spring engages said second valve closure and biases said second valve closure towards its closed position.

4. A valve apparatus according to claim 1 wherein said valve housing includes an end fitting forming one end of said second chamber furthest from said linear actuator and one of said further ports which enables flow of said heat exchange liquid into said second chamber, said end fitting providing a guiding support for said second end section of the spool.

5. A valve apparatus according to claim 4 wherein said guiding support is an integral part of said end fitting and is formed with a central axial passage into which said second end section of the spool extends for sliding movement therein.

6. A valve apparatus according to claim 1 wherein said valve housing includes a central supporting section forming a retainer for said linear actuator and separating said first and second chambers, and wherein an end section of said linear actuator is mounted rigidly in said retainer.

7. A valve apparatus according to claim 6 wherein said central supporting section is an integral part of the valve housing and is formed with a central aperture through which said piston extends.

8. A valve apparatus according to claim 1 wherein said end portion of the actuator body located adjacent said second chamber is an end plate made of said heat insulating plastic material.

9. A valve apparatus for regulating flow of a heat exchange liquid the valve apparatus being adapted for connection to a heat exchanger having flow passages for heat exchange between said heat exchange liquid and a primary liquid, operation of the valve apparatus being dependent on the temperature of said primary liquid, said valve apparatus comprising: a valve housing having first and second chambers formed therein along a longitudinal axis of the housing, first inlet and outlet ports for flow of said primary liquid in and out of said first chamber, further ports for flow of said heat exchange liquid at different temperatures in and out of said second chamber, said valve housing including a separable, one-piece end fitting forming one end of said second chamber and one of said further ports, said one further port being one inlet for said heat exchange liquid; a linear actuator mounted in said valve housing, said actuator including an actuator body containing a heat expansible material and a piston movable from a retracted position to an extended position by expansion of said material due to a predetermined increase in the temperature of said material, at least a substantial portion of said actuator body being located in said first chamber; and a valve mechanism operable by said linear actuator, located in said second chamber, and capable of controlling the flow of said heat exchange liquid through said second chamber, said valve mechanism including a valve member having a first end section engaged by said piston and an opposite second end section slidable in a guide passage formed in a valve supporting section of said end fitting.

10. A valve apparatus according to claim 9 wherein said valve member is a valve spool having a central section which is substantially wider than said first end section and is adapted to engage a valve seat formed in said valve housing when said piston is in its retracted position and said valve mechanism includes a return spring which engages said central section and thereby biases said piston towards its retracted position.

11. A valve apparatus according to claim 10 wherein said valve mechanism includes a valve closure member slidably mounted on said valve spool and movable between a closed position where said valve closure member engages a further valve seat formed on said end fitting and an open position, which allows said heat exchange liquid at an elevated temperature to flow through said one further port into said second chamber.

12. A valve apparatus according to claim 11 wherein said second end section of the valve member is a pin-like section having a relatively narrow width compared to said first end section and said central section thereof and said valve supporting section of the end fitting includes a centrally located sleeve section having apertures distributed around its periphery for flow of said coolant into said second chamber.

13. A valve apparatus according to claim 9 including a retainer clip for holding said end fitting in a main passageway formed in a main section of the valve housing, said retainer clip being received in an annular groove formed adjacent one end of the main section, and a seal extending around said end fitting and sealing a joint between said end fitting and said main section.

14. A valve apparatus for regulating flow of a heat exchange liquid which is available at a relatively low first temperature and at a relatively high second temperature, said valve apparatus comprising: a valve housing having first and second chambers formed therein and separated by an integral interior wall, first inlet and outlet ports for flow of a primary liquid into and out of said first chamber, and further ports for flow of said heat exchange liquid at said first and second temperatures into and out of said second chamber, and a valve seat arrangement, said housing including a separable one-piece end fitting forming an end of said second chamber forming one of said further ports comprising an inlet for said heat exchange liquid at said second temperatures; a linear actuator mounted in said valve housing adjacent said interior wall, said actuator including an actuator body containing a heat expansible material and a piston which, during use of the apparatus, is movable from a retracted position to an extended position by expansion of said material due to a predetermined increase in the temperature of said material because of an elevated temperature of said primary liquid in said first chamber, at least a substantial portion of said actuator body being located in said first chamber; and a valve mechanism operable by and connected to said piston of the linear actuator, located in said second chamber, and adapted to control the flow of said heat exchange liquid at each of said first and second temperatures through the second chamber, said valve mechanism including a valve member connected to said piston and movable by said piston between a closed position where said valve member engages said valve seat arrangement and an open position where said heat exchange liquid at one of said first and second temperatures can flow through and out of said second chamber during use of the valve apparatus, an end section of said valve member remote from said piston being slidable in a guide passage formed in a central valve supporting section of said end fitting.

15. A valve apparatus according to claim 14 wherein said interior wall forms a cavity and an expanded end section of said actuator body is fixedly mounted in said cavity.

16. A valve apparatus according to claim 15 including a retainer clip mounted in a groove formed inside said valve housing, said retainer clip holding said expanded end section of this actuator body in said cavity.

17. A valve apparatus according to claim 14 wherein said interior wall has a central opening formed therein and a plastic end portion of said actuator body is mounted in said central opening so as to be in contact with said heat exchange liquid in said second chamber during use of the valve apparatus.

18. A valve apparatus according to claim 14 wherein said piston is made of plastic of low thermal conductivity and said valve housing including said interior wall is also made of plastic having low thermal conductivity.